Hi @Anonymous,
I afraid that there is no any way to achieve your needs in microsoft flow currently.
Firstly,What would be the file type of the saved attachements? if the file type is not a .text type,there is no any way to get the text from the saved attachements.
Secondly,there is no any way to take a screenshot of a sheet of the xslx and the previously saved pdf in microsoft flow currently.
If you would like those features to be added in Microsoft Flow, please submit an idea to Flow Ideas Forum:
https://powerusers.microsoft.com/t5/Flow-Ideas/idb-p/FlowIdeas
Best regards,
Alice